1. Field of the Invention
The present invention relates to a new form of transistor that provides improved performance of transistor and IC chip circuits using transistors, such as for amplifier stages for audio amplifiers. More particularly, the present invention relates to a transistor that is adapted to receive a low level input signal and to substantially increase the signal gain in a single stage without significant signal distortion, and with less signal loss, less heat buildup, faster switching times, and a tolerance to higher level input signals without shutdown, as compared with existing devices.
2. Description of the Related Art
Transistors have been in use for some time in a multitude of types of electrical apparatus. They have been employed to switch circuits, to amplify voltage outputs, to amplify varying AC input signals, and to amplify inputs having varying frequencies, among other uses. Typically, transistors are semiconductor devices that have emitter-base-collector sections of either NPN or PNP configurations.
Audio amplifiers employing transistors and other circuit elements have been in use for some time for amplifying low level audio input signals to provide an amplified audio output signal of high fidelity for driving a loudspeaker. Typically, such amplifiers have a number of separate, but interconnected, stages to sequentially amplify and increase the magnitude of the incoming signal to a level sufficient to drive a suitable mechanical output device, such as a loudspeaker or a headphone.
In order to avoid excessive distortion of the incoming and amplified signal throughout the course of its passage through the several stages of the amplifier, complex circuitry has been required, involving a number of discrete circuit elements in order to properly condition the signal within and between the several amplifier stages to furnish the desired output signal level to provide the desired level and quality of sound output. Frequently, a resistor is positioned between the emitter and ground to reduce signal distortion. Further, it is known to also position a ceramic or other non-filter capacitor in parallel with the resistor. However, the capacitors that are used for that purpose are of relatively low capacitance, often of the level of around 0.01 .mu.f.
Additionally, the heat generated by existing transistor circuits often requires the addition of heat sinks to devices in which such circuits are used, in order for the transistors to function properly.
Examples of circuits that have been developed to provide a desired level and quality of output signal include those disclosed in U.S. Pat. No. 4,143,331, which issued Mar. 6, 1979, to Ronald W. Page; U.S. Pat. No. 3,210,680, which issued Oct. 5, 1965, to Paul D. Farris; and U.S. Pat. No. 4,028,634, which issued Jun. 7, 1977, to Kenneth Donald Tentarelli. In each of those patents there are disclosed circuits incorporating a plurality of interconnected transistors, some of which are NPN transistors that have their emitter junctions connected to ground through a capacitor or through a capacitor-resistor network.
It is an object of the present invention to provide a transistor that provides a comparable output in a unitary amplification stage that is normally achieved in multiple stages.
It is another object of the present invention to provide a transistor that operates at higher output levels without generating excessive heat.
It is a further object of the present invention to provide a transistor that results in faster switching and that is capable of receiving higher peaks of input signal without transistor shutdown and with less distortion than presently available transistors.
It is still a further object of the present invention to provide an improved transistor amplifier stage that provides a substantially greater gain than has heretofore been obtained in conventional transistor amplifier stages.
It is another object of the present invention to provide an improved transistor amplifier stage that incorporates fewer components than existing transistor amplifier stages.
It is still another object of the present invention to provide an improved transistor that provides a higher level of gain without distorting the output signal.